What is anthracnose?
Anthracnose (Colletotrichum graminicola ) is a turf disease pathogen that can affect turf across the UK and Ireland. It is typically viewed as the second most common turf disease, after microdochium patch. Anthracnose can affect all turf species but is most prevalent on Poa and Fescue grasses. The pathogen can result in two types of disease: foliar blight and basal rot.
How do you spot and identify Anthracnose?
With foliar blight infection the grass turns a tan-yellow colour in irregular patches. It is often mistaken for drought in the summer, particularly since the stress induced by drought can be a significant trigger for anthracnose to break out. The presence of acervuli with hair-like setae is used to diagnose foliar blight under the microscope.Basal rot begins as yellowing of older leaves on individual plants. The youngest leaf may become brick red in the later stages of development. The plant easily pulls from the turf and a black rot is visible at the base of the stem.
What causes anthracnose?
The anthracnose pathogen is commonly present in turf surfaces, but the symptoms are most likely to only occur when turf becomes stressed. Disease outbreaks are most frequently seen on golf greens and tees, bowling greens and sports pitches. Which are under the most stressful management. However, it can occur on fairways too, when conditions are conducive. Foliar blight most frequently occurs in hot, dry weather spells. Basal rot in cool, wet weather.
When does the anthracnose diseases occur in turf?
Anthracnose foliar blight often occurs in summer, whilst basal rot is normally seen in late autumn through to winter and early spring. However, conditions should be seen as the primary driver of infection, rather than calendar months.
Risk of Anthracnose infection is increased in these situations:
- The presence of Poa annua.
- When the turfgrass is under stress.
Common stresses include:
- Drought conditions
- Compacted soils
- Areas of high wear
- Inadequate nitrogen, Potassium or phosphorus
- Insect or nematode feeding
- Damage to grass plants caused by fungal pathogens
- Excessively low cutting heights.
What damage can anthracnose cause?
Infection with anthracnose reduces the playing quality of golf and bowling greens as the surface trueness is reduced. In severe cases (especially with foliar blight), loss of turf cover may occur, which may encourage the ingress of more Poa annua grass.
How do I treat anthracnose?
Fungicides can be used to treat anthracnose very effectively. Specifically Heritage Maxx and Instrata Elite (moderate control).Preventative applications provide optimum control of anthracnose. These products have label recommendations for anthracnose control in the UK.
How can anthracnose be prevented?
An Integrated Turf Management (ITM) approach will help prevent incidents of Anthracnose infection:
- Reduce the ingress of Poa annua grass into Agrostis/Festuca swards
- Accurately identify the disease(This is especially important for foliar blight, if the problem has been misidentified as drought, for example)
- Increase the height of cut
- Alleviate compaction
- Apply a nitrogenous fertiliser if the fertility is low
- Keep moisture content of soil at a sensible level
- Keep leaf wetness to a minimum using good irrigation practices and dew removal programmes
- Avoid overly dry soils by applying infrequent, deep watering
- Regularly check the Syngenta Live Disease Map for your area
Will anthracnose go away?
As climatic and stress conditions become less favorable to the disease, infection levels will subside. However, the UK’s fairly stable climate can mean that weather conditions that are favorable to high disease pressure can persist for a significant length of time.
Check the risk of anthracnose in your area here
Suggested Anthracnose Treatment Programme
Once conditions conducive to anthracnose occur, or Greencast indicates high risks of disease a preventative application of Heritage or Heritage Maxx should be applied.
This should be followed approximately 14 to 28 days later with an application of Instrata Elite if weather conditions have remained conducive.